The 45-year-old actress has admitted that her 13-year-old 'Stranger Things' co-star has had to give her a crash course in all things social media, as before working with the young actress, Winona had no idea what the photo app was.

And the 'Beetlejuice' star admits she's glad she started out as a young actress without the pressures of social media, as she doesn't know how young girls such as Millie keep up with the ''massive exposure''.

Speaking to the November issue of Marie Claire magazine, Winona said: ''I'm grateful that I got to start at the time I did. As much as I love it, I don't know if I would even have become an actor [if I was starting out now]. I wouldn't know how to [handle it]. I do worry about the massive exposure at that age.''

Meanwhile, even without being a prolific user of social media, Winona admits she finds fame to be ''overwhelming'', especially since taking on the role of Joyce Byers in the hit Netflix sci-fi horror.

She said recently: ''It's so overwhelming. I don't know what it's like for really famous people ... I keep hearing that people are dressing up like me. I'm like, 'What?'''

It isn't the first time Winona has spoken about feeling overwhelmed either, as she previously admitted she was stunned by the response to 'Stranger Things' and was ''suspicious'' of the positive reaction at first.

Winona said: ''It's been overwhelming but in a really great way. I was actually sort of suspicious at first. I'd never experienced anything like it. It's been a long time since I've been in something that was getting so much attention. And back then it was a different kind of attention. We'd stay up all night and wait for the three papers, and have someone read them first, like, 'Is it OK?'''